Web users may access and invoke various web services offered by various web service providers to obtain one or more results. A combination of web services, each outputting a respective result, may be used to obtain a single sought after result or set of results. For example, a web user may desire to obtain a list of restaurants of a certain type, e.g., seafood, that are on a route that extends from the web user's current location to another specified destination location. To do so, the web user might perform a keyword search for seafood restaurants in city x, select the links to the returned restaurant listings to obtain an address, provide each address to a web service for obtaining a corresponding geographic code, instantiate a direction providing service for obtaining a route from the web user's current location to the destination location, and enter the route and the geographic codes into a comparison web service for finding the points along the route to which the geographic codes are respectively determined to be closest and for returning only those of the codes that are within a threshold distance of the route. Separately interfacing with the various web services is tedious.
Traditional resource management systems use a variety of incompatible and proprietary interfaces and protocols. These demand intensive manual work (e.g., programming) when new resources are available. Hewlett-Packard (HP) provides a Web Service Management Framework (WSMF) that is a logical architecture for managing distributed computing resources and that has been proposed to address this issue by leveraging the extensibility and loose coupling offered by the web service technology. It defines a standard and platform-independent protocol for extraction of management information. The protocol is extensible for supporting more complex IT management issues as new standards appear for security, routing, discovery, etc.
Three key concepts of the WSMF are managed objects, event notification, and relationships. A managed object provides management capabilities via management interfaces. Resources are modeled as managed objects that have certain relationships between each other. The managed objects provide a set of management interfaces via which the underlying resources can be managed. The managed objects are web services because the management interfaces are described using the Web Service Definition Language (WSDL) and managing a resource can be achieved by accessing a web service. This enables managers to manage resources of a domain in a uniform manner.
The WSMF includes an event subsystem, which defines operations to subscribe for event notifications and specifies the notification syntax and processing rules to inform subscribers once an event occurs. An event may represent a state change in a managed resource. It may also represent the processing of a request by the managed resource that can be communicated via a notification.
Relationships defines the behavior and the dependencies between managed objects. They essentially reflect the relationships between the underlying resources. A relationship describes the association type between two managed objects.
The Organization for the Advancement of Structured Information Standards (OASIS) provides Web Services Distributed Management (WSDM), which specifies how the manageability of a resource is made available to manageability consumers via web services. WSDM leverages the integration capacity of web services for resource management purpose. Web service technologies are used to integrate management applications that are used to manage heterogeneous IT resources. This helps setup a management infrastructure that is vendor-neural, platform independent, and allows using a common messaging protocol between a manageable resource and a manageability consumer.
Three key components in the WSDM architecture are the manageable resource, endpoint reference, and manageability consumer. The manageable resource may be represented as a web service and accessible via a web service endpoint. The endpoint is referenced by an endpoint reference, which is defined in the WS-Addressing specification. The reference point provides the target location to which a manageability consumer can direct messages.
The WSDM supports three modes of interactions among the three components. A manageability consumer may retrieve management information from the manageable resource. A manageability consumer may affect the state of the manageable resource by changing its management information. A manageable resource may notify a manageability consumer about a significant event. The WSDM also offers a set of facilities to support the above interactions, including a resource property document, manageability capabilities, management events, message exchange patterns, and advertisement.
Microsoft (MS) also presents a Web Services Management specification, called WS-Management, with a similar purpose as the WSMF and WSDM of HP and OASIS, respectively. A common objective of the Web Service Management Systems from all these industrial players is to address the cost and complexity of IT management by using web service technology. They offer a resource management solution at the enterprise level. The user group of these management systems would be entrepreneurs or resource managers.